The My Location feature takes information broadcast from mobile towers near you to approximate your current location on the map -- it's not GPS, but it comes pretty close (approximately 1000m close, on average).

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[It's] available for most web-enabled mobile phones, including Java, Blackberry, Windows Mobile, and Nokia/Symbian devices.

Until GPS radios come standard in every mobile "phone" (and they will), this seems like a viable stopgap.